The invention is directed to processes using movable particles in a fluid mixture, as well as to said particles per se, which particles may be used in such processes. Processes in which the particles can be employed in accordance with the present invention are for instance processes that involve separation of compounds, catalytic processes, as well as cleaning of process equipment, such as membranes, heat exchangers, etc. and/or controlled release of compounds.
The removal of components from liquid mixtures by contacting the mixture with heterogeneous materials, so as to attain sorption (the term “sorption” including absorption and/or adsorption) from the component on the heterogeneous material gives in practice frequently rise to difficulties in operation, in particular with the separation of the solid materials from the fluid. These difficulties are increased if other solid particles are present in the liquid, such as micro-organisms, which are usually present in biological production processes. With regard to biological production processes, it is at the same time usually very important to remove the products produced by the micro-organisms, because these micro-organisms often suffer from product inhibition, which is noted already at very low concentrations of the product formed. Therefore, the product is preferably removed as quickly as possible at low concentrations. Furthermore, it is highly desired if this removal of product may be carried out with relatively small process amendments, preferably by a single unit-operation. It is thus very important to develop means that can effectively separate compounds from (biological) reaction mixtures and other types of mixtures.
It is an object of the present invention to provide a separation process that meets the above-mentioned requirements.
US-A-2003/0104359 describes a separation method in which target material is coupled to encapsulated microbubbles, which are allowed to float to the surface to form a floating layer.
U.S. Pat. No. 6,035,924 describes a method for casting a metal article in which a molten metal is led through an insulating layer of hollow spheres, floating on a fluidized bed.